Solar and Shore Power Living Together In Perfect Harmony? - RV-Dreams Community Forum

365vacay · RV-Dreams Community Member

Solar and Shore Power Living Together In Perfect Harmony?

solo boondocker · RV-Dreams Family Member

365vacay wrote:
I have solar power (panel, converter, inverter, and battery). Everything is working fine, but I would also like to be able to use shore power to charge the batmonthnd run existin. lights and fan sometime.
Can I just use the same battery that I have hooked up to my solar to my travel trailer's existing connection?
Any insight you can offer is greatly appreciated.
If it helps, I have a 1981 Serro Scotty.

Just plug it in. Unless whoever installed the system did something odd, your converter will charge your battery bank. Your solar controller may not do anything while plugged in but you don't need it. If you still have the original converter, check the battery water a couple of times a month and you'll be fine.

I'm a big believer in the KISS formula and "If it ain't broke, don't fix it." Right now I am plugged in at a city campground in Mobile, AL. When I leave I won't do anything but unplug. When the battery voltage drops to level determined by electronic gremlins, the solar panel will start doing something useful.

I use a seperate extra charger to put a lot of amps into my batteries from a very small generator. This gets the initial or "bulk" charge over quickly and then the solar takes care of the rest. If you boondock a lot you might consider something similar.

Solo boondocker

carolinakids · RV-Dreams Family Member

Our inverter has a charger in it. We have the original converter/charger breaker cut off. If I see the chargers not working we can cut the original back on to charger batteries if hooked to shore power. Look inside your electrical panel and see if they cut breaker to converter/charger off in case yours does this.

bjoyce · RV-Dreams Family Member

Our inverter/charger, a Magnum, has a switch for the charger on the control panel and there is no need to turn off a breaker. Our previous inverter/charger, a Prosine, also had a switch. When in sun and on metered electric shore power, I have turned off the charger on the inverter/charger and used solar to keep the batteries charged. You have to make sure all of your charging sources are set for your particular batteries and not set to defaults. Defaults can be OK, or very bad. On the Prosine the default was 200 Amp-hours of Gel batteries, which kept the charging rate and voltage too low for most other batteries.

Bill and Linda · RV-Dreams Family Member

bjoyce wrote:
Our inverter/charger, a Magnum, has a switch for the charger on the control panel and there is no need to turn off a breaker. Our previous inverter/charger, a Prosine, also had a switch. When in sun and on metered electric shore power, I have turned off the charger on the inverter/charger and used solar to keep the batteries charged. You have to make sure all of your charging sources are set for your particular batteries and not set to defaults. Defaults can be OK, or very bad. On the Prosine the default was 200 Amp-hours of Gel batteries, which kept the charging rate and voltage too low for most other batteries.

Bill J's comments are a big deal, especially as pertains to battery life. When asked to look at chargers, more often then not, I find the "factory" has installed the high dollar charger / inverter and left the settings at default. Not only can this mean over or under charging the batteries, it can mean if there are battery monitoring read outs - how many battery amp hours have been used - these will be totally false if the charger / monitor is not properly set for the installed battery bank size. One setting does not fit all.

We have friends in an expensive new motor home who went through 2 sets of AGM batteries before some technician "finally" thought to check the charger / inverter settings before installing the third set. The charger was damaging the batteries due to continuous over charging.

It's really important the solar and AC chargers are set as close as possible to the battery manufacture's recommendations. Not only for longer battery life, but to have all the amp hours one has paid for with an expensive battery bank. Inexpensive chargers and solar controllers may not have many setting options. That's why they are inexpensive.

bjoyce · RV-Dreams Family Member

Another point is to write down (or save to a file or note app) the settings on your chargers. A part swap or other work on the electric system might cause one of the chargers to get reset or lose its settings. You want to be able to get them back. I know of cases where the factory got the settings correct, but the dealer fixed something and they went back to defaults.

Two true stories:
1) A friend was at the Newmar factory service center in Indiana when a new motorhome drove in for an appointment. The motorhome was not charging the batteries and the dealer had already replaced the batteries once, so they recommended driving from Oregon to Indiana so Newmar could fix the charging system. My friend turned the charger switch on the inverter/charger back on and the problem was solved. The owner and the dealer didn't notice it was turned off. Newmar says this happens all the time since dealers are more familiar with converters, which have no charger on/off switch, then inverter/chargers that do and therefore don't realize the charger can be turned off.
2) We were at a rally where a dealer had brought multiple used RVs to sell. The dealer was having problems popping breakers on the shore power, so one of their salespeople went into all the units with inverter/chargers and turned the chargers off or set the charger to minimum amps. This "fixed" the problem with popping breakers. A couple days later the dealer was using external battery chargers to try to charge dead batteries on multiple RVs. (I said "try to" since they had to replace some of the batteries.)

Bruce and Robin · RV-Dreams Family Member

Great discussion. I have not had a chance to check my systems thoroughly yet since I just purchased the 2014 DRV Mobile Suite RV and I am not in it yet. I will be this coming week though, FT, and it is a little nerve racking to say the least. To my question, I have a 1000W pure sine wave Magnum Inverter with built in charger for the residential fridge. It also has a Converter Charger Progressive Dynamics PD9280 Wizard, Input 105-130 VAC - 1300Watts Output 13.6 VDC 80 Amps. I have 2 - 6V Interstate probably GC but not sure batteries. All that said, can you tell me how they might have set this up for charging the batteries when they both, ( inverter & converter ) have charging capabilities? I do not have solar yet. I probably will upgrade at some point and go with the AGM batteries. I would like a minimum of 4 - 6V batteries without solar. I know this converter wizard controller has 4 charging modes. 14.4V Boost Mode which returns the battery to 90% in about 8 hours, Normal Mode 13.6V - requires 40 hrs to return the battery to 90%, Storage mode 13.2V requires 60 hrs to return the battery to 90%, and Equalize Mode when in Storage Mode the microprocessor automatically increases the output voltage to 14.4 volts DC for 15 minutes every 21 hours. If all this is happening from the converter, what is the inverter charger doing? Maybe the inverter charger is not on.

-- Edited by Bruce and Robin on Saturday 18th of February 2017 03:20:12 PM

Bill and Linda · RV-Dreams Family Member

According to the spec sheets on the products, "they" didn't set up anything. These products fall into the simple "nothing to set up" category. They are fixed as to their settings. The Inverter / Charger spec sheet is not totally clear. It sort of implies the charger is an option depending on where one reads. Your guess the charger is not turned on is probably correct if it is an option as a charger is not included with the inverter in question. There would be no reason to to have two, 120 volt supplied chargers operating at the same time. (Different situation than having a backup charger which some of us do.)

This is a generalization - With the proliferation of residential refrigerators in RV's manufactures are now installing small, basic, 12 to 120 volt inverters to run the fridges during relatively short day periods of travel. I've seen quite a number of two-battery, with relatively small batteries, installations with a small 1,000 watt inverter to supply generally only the residential refrigerator. Along with these are separate, stand alone 3-stage but fixed setting battery chargers appropriate for small led-acid battery banks. Nothing wrong with this whatsoever. But this setup is a long way from the higher power inverter / charger capabilities Bill J and I have been generally referring to using larger AGM type battery banks more appropriate for boondocking, etc.

Hope that helps.

LarryW21 · RV-Dreams Family Member

"some technician "finally"...

Gee, Bill, I'd rag on the other technicians but not the one that finally diagnosed the isssue. To him/her I'd thank profusely.